Formal or casual? How to pick the right Korean

Korean grammar textbooks list seven speech levels. You need two of them. Here is which two, and how to tell which one a situation calls for.

Every phrase on this site is listed twice: a casual form and a polite form. That is not a formatting habit, it is the single largest difference between Korean and English, and it is the thing that most often makes a learner sound wrong even when every word is right.

In English, the difference between talking to your friend and talking to your friend's father lives in your word choice and your tone. In Korean it lives in the verb ending, and it is not optional. You cannot speak a Korean sentence without choosing one.

The two endings you need

Textbooks will show you seven levels. In daily life, two of them cover almost everything you will ever say.

This is your default, and if you learn only one ending, learn this one. It is polite without being stiff. You can use it with a shopkeeper, a taxi driver, a colleague, your friend's mother, and a stranger who asks you the time. Nobody will ever be offended by it.

This is 반말 (banmal), the plain form. You use it with close friends your own age or younger, with children, and with family members younger than you. Notice what is missing: it is not for anyone older, even by a couple of years, until they tell you it is fine.

The good news is that going from one to the other is usually a single syllable. Take the casual form and add 요:

• ▶
  고마워 → 고마워요

  thanks → thank you
• ▶
  괜찮아 → 괜찮아요

  it is fine → it is fine (polite)
• ▶
  배고파 → 배고파요

  I am hungry → I am hungry (polite)

The third one you will hear but rarely say

There is a formal register above 해요, ending in -습니다 / -ㅂ니다. You will hear it constantly and produce it rarely. It belongs to news broadcasts, airline announcements, military service, job interviews, and the moment a shop assistant greets you at the door.

Two exceptions are worth memorising as fixed units rather than as grammar, because you will use them on your first day: 고마워 (gomawo) and the formal apology 미안해 (mianhae). In both cases the formal version is so common that using the casual one with a stranger sounds careless.

How to choose, in practice

Age and relationship decide it, and Korean conversations establish age early for exactly this reason. The question 몇 살이에요? (how old are you) is not small talk — it is the speaker working out which grammar to use for the rest of the conversation.

The practical rule is simple:

What actually happens if you get it wrong

Less than learners fear, and more than they expect.

If you are visibly a foreigner speaking Korean, using 반말 by accident reads as a beginner mistake, not as rudeness. People are generous about it. What they are less generous about is the reverse situation — a learner who has been in Korea for years and still addresses everyone identically, because at that point it stops looking like a gap in grammar and starts looking like a gap in attention.

The place it genuinely matters early is service settings, where a casual form aimed at someone serving you lands badly. This is why the 난 괜찮아 (nan gwaenchana) page recommends 이제 충분해요 over the blunter alternative, and why 저기요 (jeogiyo) is worth learning in its polite shape first.

One more wrinkle: honorifics are not the same thing

Speech level is about who you are talking to. Korean has a second, separate system for who you are talking about, and it works by inserting -시- into the verb.

• ▶
  어디 가요?

  eodi gayo?

  Where are you going? — polite to the listener
• ▶
  어디 가세요?

  eodi gaseyo?

  Where are you going? — polite to the listener AND raising them

The second is what you say to someone older. You will meet it most often in fixed phrases — 안녕하세요 and 안녕히 주무세요 both carry it — so you will be using honorifics correctly long before you learn the rule.

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